The present invention relates to a mechanical chain tensioner of the type used, for example, in an internal combustion engine.
In a mechanical chain tensioner of such a type, which is known in practice, the basic body is a punched/bent part from a sheet metal having a constant wall thickness. The basic body has an arcuate vertical web, on the concave bottom side of which a transverse wall is bent for reasons of stiffness. Two punched holes form fastening openings in which bushings are riveted, or into which bushings are pressed and welded. An abutment for the tension bracket is a bearing pin which has been riveted into the web, and onto which the tension bracket is slid in the longitudinal direction of the pin and is secured by an additional securing element against withdrawal. The basic body is expensive in production and heavy. It must, so to speak, be tailored to every mode of fastening, since the distances of the fastening openings are different for different types of internal combustion engines. Moreover, the basic body requires a surface treatment.
In a chain tensioner which is known from EP-A-0 581 219, a solid, metallic support is provided for the tension bracket.
In a chain tensioner which is known from EP-A-0 195 945, a guide housing is provided for the piston in the chain tensioner carrier, which is made of metal. The tensioning rail of the chain tensioner is made of plastics for reasons of cost and weight.